Search results for "FEMTOSECOND"
showing 10 items of 238 documents
Femtosecond parabolic pulse shaping in normally dispersive optical fibers
2013
Formation of parabolic pulses at femtosecond time scale by means of passive nonlinear reshaping in normally dispersive optical fibers is analyzed. Two approaches are examined and compared: the parabolic waveform formation in transient propagation regime and parabolic waveform formation in the steady-state propagation regime. It is found that both approaches could produce parabolic pulses as short as few hundred femtoseconds applying commercially available fibers, specially designed all-normal dispersion photonic crystal fiber and modern femtosecond lasers for pumping. The ranges of parameters providing parabolic pulse formation at the femtosecond time scale are found depending on the initia…
All-fiber spectral compression of picosecond pulses at telecommunication wavelength enhanced by amplitude shaping
2012
International audience; We demonstrate efficient spectral compression of picosecond pulses in an all-fiber configuration at telecommunication wavelengths. A spectral compression by a factor 12 is achieved. Performing temporal shaping with a parabolic pulse significantly improves the spectral compression with much lower substructures and an enhanced Strehl ratio.
Experimental properties of parabolic pulses generated via Raman amplification in standard optical fibers
2004
Parabolic pulses at 1550 nm have been generated in a standard telecommunications fiber using Raman amplification. The parabolic output pulse characteristics are studied as a function of input pulse energy and duration.
Ultra-flat SPM-broadened spectra in a highly nonlinear fiber using parabolic pulses formed in a fiber Bragg grating
2006
International audience; We propose a new method for generating flat self-phase modulation (SPM)-broadened spectra based on seeding a highly nonlinear fiber (HNLF) with chirp-free parabolic pulses generated using linear pulse shaping in a superstructured fiber Bragg grating (SSFBG). We show that the use of grating reshaped parabolic pulses allows substantially better performance in terms of the extent of SPM-based spectral broadening and flatness relative to conventional hyperbolic secant (sech) pulses. We demonstrate both numerically and experimentally the generation of SPMbroadened pulses centred at 1542nm with 92% of the pulse energy remaining within the 29nm 3dB spectral bandwidth. Appli…
Supercontinuum generation at 800 nm in all-normal dispersion photonic crystal fiber
2014
We have numerically investigated the supercontinuum generation and pulse compression in a specially designed all-normal dispersion photonic crystal fiber with a flat-top dispersion curve, pumped by typical pulses from state of the art Ti:Sapphire lasers at 800 nm. The optimal combination of pump pulse parameters for a given fiber was found, which provides a wide octave-spanning spectrum with superb spectral flatness (a drop in spectral intensity of ~1.7 dB). With regard to the pulse compression for these spectra, multiple-cycle pulses (~8 fs) can be obtained with the use of a simple quadratic compressor and nearly single-cycle pulses (3.3 fs) can be obtained with the application of full pha…
Ultra-short pulse propagation in birefringent fibers—the projection operator method
2008
We examine the propagation of ultra-short optical light pulses in dispersion-managed birefringent fiber transmission systems, in which the pulse dynamics is governed by the coupled higher-order nonlinear Schrodinger equations with higher-order linear and nonlinear optical effects. We derive the equations of motion in terms of pulse parameters such as amplitude, temporal position, width, chirp, frequency and phase, using a projection operator method, and we obtain the spatial dynamical behavior of picosecond and femtosecond pulse parameters. From our detailed analysis, we show that the stimulated Raman scattering has a strong impact on the pulse dynamics.
Parabolic Pulse Amplifiers
2008
International audience; Recent studies in nonlinear optics have led to the discovery of a new class of ultrashort pulse generated in fiber amplifiers by the self-similar propagation of an arbitrary input pulse. These pulses with a parabolic shape and linear chirp, called `optical similaritons,' represent asymptotic solutions of the nonlinear Schrödinger equation with gain, towards which any initial pulse of given energy converges, independently of its intensity profile. Parabolic pulse amplifiers can be easily developed with standard optical fibers and commercial devices. Our goal here is to emphasize the main properties of similaritons and to discuss a few of their numerous new application…
Pulse quality analysis on soliton pulse compression and soliton self-frequency shift in a hollow-core photonic bandgap fiber.
2013
A numerical investigation of low-order soliton evolution in a proposed seven-cell hollow-core photonic bandgap fiber is reported. In the numerical simulation, we analyze the pulse quality evolution in soliton pulse compression and soliton self-frequency shift in three fiber structures with different cross-section sizes. In the simulation, we consider unchirped soliton pulses (of 400 fs) at the wavelength of 1060 nm. Our numerical results show that the seven-cell hollow-core photonic crystal fiber, with a cross-section size reduction of 2%, promotes the pulse quality on the soliton pulse compression and soliton self-frequency shift. For an input soliton pulse of order 3 (which corresponds to…
High-quality optical pulse train generator based on solitons on finite background
2013
International audience; We report a simple method to exploit the typical properties of solitons on finite background in order to generate high repetition rate and high quality optical pulse trains. We take advantage of the nonlinear evolution of a modulated continuous wave towards localized structures upon a nonzero background wave in anomalous dispersive fiber. After a stage of nonlinear compression, a delay-line interferometer enables the annihilation of the finite background and simultaneously allows the repetition rate doubling of the pulse train.
Tailored waveform generation in mode-locked fiber lasers by in-cavity pulse shaper
2014
International audience; We numerically show the possibility of pulse shaping in a mode-locked fiber laser by inclusion of an amplitude-phase spectral filter into the laser cavity. Various advanced temporal waveforms are generated, including parabolic, flat-top and triangular pulses.